In wellbore operations it is often desirable to identify characteristics, such as the composition, of the wellbore fluid at identifiable locations in the wellbore. For example, in some circumstances it may be desirable to identify at what location in the wellbore that water, gas, or oil is entering from the surrounding formation. It may further be a desire to identify the presence of hydrogen sulfide or carbon dioxide.
It is a desire of the present invention to provide methods and apparatus for determining the composition and/or characteristics of wellbore fluids in the wellbore. It is a still further desire to provide optical fiber sensors for determining wellbore fluid characteristics. It is a still further desire to provide optical sensors and methods for determining the chemical composition of a wellbore fluid, in the wellbore, without requiring in-tool fluid sampling.